This disclosure relates to a display device capable of a detecting an external proximity object, and in particular, to a display device with a touch detection function detecting touch events based on a change of an electrostatic capacitance, a drive circuit, a driving method of a display device with a touch detection function, and an electronic unit including the display device, the drive circuit, and the driving method.
In recent years, a display device capable of inputting information by mounting a touch detection function detecting an external proximity object such as a finger, on a display device such as a liquid crystal display device, and displaying various button images on the display device instead of typical mechanical buttons has attracted attention. The display device including such a touch detection function does not require input devices such as a keyboard, a mouse, and a keypad, and therefore there is a tendency to expand the use of such a display device to portable information terminals such as a mobile phone, in addition to a computer.
Some methods are included in the touch detection method, and one of them is an electrostatic capacitance method. For example, in Japanese Unexamined Patent Application Publication No. 2009-258182, a display device in which a common electrode which is for display and is originally arranged in the display device is also used as one electrode of a pair of touch sensor electrodes, and the other electrode (touch detection electrode) is arranged to intersect with the common electrode has been proposed. An electrostatic capacitance is formed between the common electrode and the touch detection electrode, and the electrostatic capacitance is changed in response to an external proximity object. The display device uses the change of the electrostatic capacitance to analyze a touch detection signal which appears in the touch detection electrode in response to application of a touch detection drive signal to the common electrode, thereby detecting the external proximity object. In the display device, display operation is performed by sequentially applying the drive signal to the common electrode to perform line-sequential scanning, and the touch detection signal which appears in the touch detection electrode is analyzed according to the drive signal to perform touch detection operation.